The present disclosure relates to manufacturing processes for cord style golf grips of the type having exposed cord material embedded in the grip for enhancing gripability. The presence of exposed cords in a flexible rubber golf grip has attained widespread popularity and has enjoyed a growing market. However, the processes for manufacturing such a grip have proven to be somewhat complex and labor intensive thereby increasing the cost of the grips.
Referring to FIG. 1, an example of the current manufacturing process employed for a corded rubber golf club grip is shown wherein an upper and lower rubber sheet 10, 12 are employed which have been previously prepared by calendering uncured rubber to a desired predetermined thickness which may require multiple passes through the calender to achieve the desired dimensional thickness. The sheets 10, 12 are disposed on opposite sides of the desired fabric or corded layer 13 and passed through idler nips indicated generally at 16, 18, 20. The three layers are then fed through a pair of calender rollers 22, 24 which compress and force the sheets together to a common single sheet stock indicated generally at 26 for further processing.
Another alternative technique currently employed is that of laying out the sheets 10, 12 on long tables and coating the surface of the sheets with solvent bonding agent and manually laying the sheets over the fabric or cord layer such that the cords are sandwiched between the sheets. The sheets with the fabric layer in between can then be run through a calender to achieve the desired thickness of the sheet stock. This latter technique is even more time consuming and costly for preparing the sheet stock.
Referring to FIG. 2, the presently known process for manufacturing is continued wherein the sheet stock 26 is passed through a stamping press, indicated generally at 28, which die cuts desired pattern pieces 30 out of the sheet stock 26 which pattern pieces are then removed and have the general form illustrated in FIG. 3. It will be seen that there is a considerable amount of scrap material on the sheet stock after die cutting the pattern pieces 26. In addition, the fabric layer 14 is quite costly due to the fact that the fabric is specially woven for golf grip manufacture and is thus a relatively low volume item for fabric mills. Attempts have been made to offset the cost of the fabric by buying standard fabric manufactured in high volume; however, this necessarily limits the choices for type of cord and the amount of variation in cord pattern that can be employed in the fabric for the corded grip. This results in limited variation in the style of the grip which can be offered for enhancing marketability.
Referring to FIGS. 4 and 5, the existing known manufacturing process is continued by wrapping the pattern pieces 26 individually about core rods 33 and placing the pattern pieces and core rods individually in cylindrical pre-mold cavities 32 formed in a pre-mold section 34 and closing the pre-mold with an upper pre-mold section 36 having remaining cylindrical pre-mold cavities 38 formed therein. In the currently known process, the die cut pattern pieces 30 each comprise one-half the periphery of the molded rubber grip and this requires that one of the pattern pieces 30 be loaded in each molded cavity in both the upper and the lower halves 34, 36 of the mold as shown in FIG. 4. The pre-mold is then heated to effect only partial curing of the grip and the pre-mold is then opened and the partially cured preform grips and core rods removed from the mold. One of the preform grips is shown in FIG. 5 with the pattern pieces 30 wrapped around rod 33.
The preform grip of FIG. 5 and core rod are then manually placed in a heated compression mold cavity along with an end cap which molds the preform into a finished golf grip shape.
Thus, it can be seen from the preceeding description that the present process for manufacturing corded flexible rubber golf club grips is not only time consuming by virtue of requiring multiple manual steps but also yields much scrap material which results in significantly increased cost for manufacturing the grip as compared with, for example, an uncorded golf club grip.
Thus, it has long been desired to provide a way or means of manufacturing a corded flexible rubber golf club grip in a manner which permits wide variation of styles of appearance for the grip and yet is less complex and has a significantly reduced manufacturing cost.